標題: electrical problem [打印本頁] 作者: 心心 時間: 2009-1-13 23:36 標題: electrical problem
A copper rod, 0.4m long and 4.0mm in diameter, has a resistance of 550μΩ at 20℃. Calculate the resistivity of copper at that temperature. If the rod is drawn out ito a wire having a uniform diameter of 0.8mm, calculate the resistance of the wire when its temperature is 60℃. Assume the resistivity to be unchanged and the temperature coefficient of resistance of copper to be 0.00426/℃.
